HDMI sound not working

[Jaap Boender <jaapb%kerguelen.org@localhost>]

Hello list,

I've got a slightly baffling problem - HDMI sound is not working on my 
NetBSD-current installation (9.99.93, last updated yesterday, Feb 16).

I've got a setup with two sound cards: the on-board sound chip, and the 
graphics card (a Radeon RX550). These both seem to be dectected (after 
adding the HDAUDIO_ENABLE_HDMI option to the kernel config), as the 
dmesg shows:

[     1.015262] hdaudio0 at pci9 dev 0 function 1: HD Audio Controller
[     1.015262] hdaudio0: interrupting at msi3 vec 0
[     1.015262] hdaudio0: HDA ver. 1.0, OSS 5, ISS 0, BSS 0, SDO 1, 64-bit
[     1.015262] hdafg0 at hdaudio0: vendor 1002 product aa01
[     1.015262] hdaudio1 at pci11 dev 0 function 4: HD Audio Controller
[     1.015262] hdaudio1: interrupting at msi5 vec 0
[     1.015262] hdaudio1: HDA ver. 1.0, OSS 4, ISS 4, BSS 0, SDO 1, 64-bit
[     1.015262] hdafg1 at hdaudio1: vendor 10ec product 0897
[     1.015262] audio0 at hdafg1: playback, capture, full duplex, 
independent
[     1.015262] audio0: slinear_le:16 2ch 48000Hz, blk 1920 bytes (10ms) 
for playback
[     1.015262] audio0: slinear_le:16 2ch 48000Hz, blk 1920 bytes (10ms) 
for recording
[     1.015262] spkr1 at audio0: PC Speaker (synthesized)
[     1.022324] hdaudio0 at pci9 dev 0 function 1: HD Audio Controller
[     1.022324] hdaudio0: interrupting at msi3 vec 0
[     1.022324] hdaudio0: HDA ver. 1.0, OSS 5, ISS 0, BSS 0, SDO 1, 64-bit
[     1.022324] hdafg0 at hdaudio0: vendor 1002 product aa01
[     1.022324] audio0 at hdafg0: playback
[     1.022324] audio0: slinear_le:16 2ch 48000Hz, blk 1920 bytes (10ms) 
for playback
[     1.022324] spkr1 at audio0: PC Speaker (synthesized)
[     1.022324] hdaudio1 at pci11 dev 0 function 4: HD Audio Controller
[     1.022324] hdaudio1: interrupting at msi5 vec 0
[     1.022324] hdaudio1: HDA ver. 1.0, OSS 4, ISS 4, BSS 0, SDO 1, 64-bit
[     1.022324] hdafg1 at hdaudio1: vendor 10ec product 0897
[     1.022324] audio1 at hdafg1: playback, capture, full duplex, 
independent
[     1.022324] audio1: slinear_le:16 2ch 48000Hz, blk 1920 bytes (10ms) 
for playback
[     1.022324] audio1: slinear_le:16 2ch 48000Hz, blk 1920 bytes (10ms) 
for recording
[     1.022324] spkr2 at audio1: PC Speaker (synthesized)

But I can't actually hear anything over the HDMI audio (which works 
under Windows, so it's not the device itself that is at fault).

audioctl looks okay as far as I can see, the right device is selected:
0: [*] audio0 @ hdafg0: vendor 1002 product aa01
       playback: 2ch, 48000Hz
       record:   unavailable
       (P-) slinear_le 16/16, 2ch, { 32000, 44100, 48000 }
       (  ) ac3 16/16, 2ch, { 32000, 44100, 48000 }
       (PR) slinear_le 16/16, 2ch, 48000-48000Hz
1: [ ] audio1 @ hdafg1: vendor 10ec product 0897
       playback: 2ch, 48000Hz
       record:   2ch, 48000Hz
       (PR) slinear_le 16/16, 2ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 16/16, 4ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 16/16, 6ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 16/16, 8ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (PR) slinear_le 20/32, 2ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 20/32, 4ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 20/32, 6ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 20/32, 8ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (PR) slinear_le 24/32, 2ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 24/32, 4ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 24/32, 6ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (P-) slinear_le 24/32, 8ch, { 32000, 44100, 48000, 88200, 96000, 
192000 }
       (  ) ac3 16/16, 2ch, { 32000, 44100, 48000, 88200, 96000, 192000 }
       (  ) ac3 16/16, 4ch, { 32000, 44100, 48000, 88200, 96000, 192000 }
       (  ) ac3 16/16, 6ch, { 32000, 44100, 48000, 88200, 96000, 192000 }
       (  ) ac3 16/16, 8ch, { 32000, 44100, 48000, 88200, 96000, 192000 }

but mixerctl -a gives only this:
outputs.dacsel=HDMI00,HDMI01,HDMI02,HDMI03,HDMI04

though audioctl -a does get me a bunch of stuff:
name=vendor 1002
version=product aa01
config=01h
encodings=mulaw:8*,alaw:8*,slinear:8*,ulinear:8*,slinear_le:16*,ulinear_le:16*,slinear_be:16*,ulinear_be:16*,slinear_le:32*,ulinear_le:32*,slinear_be:32*,ulinear_be:32*
properties=mmap
full_duplex=0
fullduplex=0
blocksize=2048
hiwat=32
lowat=24
monitor_gain=0
mode=
play.rate=48000
play.channels=2
play.precision=32
play.encoding=slinear_le
play.gain=127
play.balance=32
play.port=0x0
play.avail_ports=0x0
play.seek=0
play.samples=0
play.eof=0
play.pause=0
play.error=0
play.waiting=0
play.open=0
play.active=1
play.buffer_size=65536
record.rate=8000
record.channels=1
record.precision=8
record.encoding=mulaw
record.gain=127
record.balance=32
record.port=0x0
record.avail_ports=0x0
record.seek=0
record.samples=0
record.eof=0
record.pause=0
record.error=0
record.waiting=0
record.open=0
record.active=0
record.buffer_size=65536
record.errors=0

Is this a case of this particular device not being supported (enough) by 
NetBSD, or did I misconfigure something? Happy to provide more 
information if needed.

best,

  Jaap